Baxi Bermuda Luke-warm Radiators

[lawdevice]

From reading your forum I think I need to flush my radiators and put somekind of chemical into my system?

Here's my situation...

We're getting hardly any heat out of our radiators at the moment.

We moved into the house in April (it's been seriously neglected) and I've only recently turned my attention to the heating system.

I noticed a few weeks ago that only a couple of the radiators got warm. So I did a bit of research and decided I needed to bleed and balance the rads.

I opened all the valves on all the rads which resulted in all the upstairs ones getting incredibly hot and all the downstairs ones staying ice cold. Which isn't suprising is it?

So I then closed all the upstairs rads completely off. This resulted in one downstairs rad getting reasonably hot and the rest just luke-warm.

Then I closed all of the valves and went round one radiator at a time opening the valve and letting them get piping hot. So I know all of the radiators are capable of getting hot.

What I've ended up with is all the upstairs valves hardly on (less than 1/8 turn open) and all the downstairs fully open. I've turned the pump up from 3 to 4 and I'm left with all the radiators getting to a similar temperature (barely warm at all).

It says Baxi Bermuda C2 on the gas fire and the boiler's in the chimney behind it. It's a very old system but British Gas said the previous owners had it serviced yearly.

The radiators downstairs look really old and the radiators upstairs say "Plumb Centre" on them and look reasonably new.

Thanks Guys,
Dave

 

[lawdevice]

I forgot to say...

The pipes connected to the downstairs radiators, one gets piping hot and the other is stone-cold.

 

[JohnD]

A chemical clean, flush, rinse and refill with inhibitor is probably a good idea, especially if the water that comes out when you bleed rads is black, or if you find sediment in the bottom of the header tank (if so, bale and sponge it out). It is fairly inexpensive and easy to do yourself but takes a bit of time. If you are fond of plumbing and have £100 to spare you could also fit a Magnaclean which will trap circulating black particles and sludge out of the water.

However, (assuming that the system also heats the hot water cylinder) there is also a possibility that flow is going to the cylinder instead of to the rads.

Have a feel of the pipes leaving the pump; look and see if it has an electrically operated valve, and see if the pipe going to the cylinder is very hot.

If it has an electric valve, they can get worn with age and allow flow to leak past to the cylinder.

It is also possible that the pump is worn out.

If it used to be on a BG service contract, are you able to renew it in your own name? BG annual services perform a safety check, but often don't do much else unless you have a fault and ask them to fix it. They are very willing to replace pumps and valves if worn or faulty.

BG will probably offer you a power flush at £600 if there is a possibility you have sludge (which most old systems do).

If the radiators are all equally warm and the boiler is running full on, there is also a possibility that the radiators can take more heat than the boiler produces. I don't know the output but if you say number and sizes or rads someone probably will.

If the pump is hotter than the pipes going into it then it is probably jammed or blocked.

I am not a plumber or heating engineer so only know about simple things.

 

[lawdevice]

here is also a possibility that flow is going to the cylinder instead of to the rads.

Have a feel of the pipes leaving the pump; look and see if it has an electrically operated valve, and see if the pipe going to the cylinder is very hot.

If it has an electric valve, they can get worn with age and allow flow to leak past to the cylinder.

The heating's been on for about an hour, so I've just been and felt the pipes...

The pipe goes from the pump to a Honeywell Y Plan valve. One pipe goes to the water cylinder and the other must go to the radiators? It's equally warm on both sides.

Over the summer I noticed the Y Plan valve was making a weird noise... when the heating turned on, kind of a weird vibrating/electrical noise. I haven't noticed it recently. (Is this because during the summer the valve was heating the water and not going to the radiators?).

 

[JohnD]

Feel it again at a time when the hot taps have not been run for half an hour (so the cylinder should not be taking any supply).

You should be able to find the cylinder stat stapped to the side of the cylinder. When it reaches temperature the valve should shut off supply to the cylinder.

There is probably a lever on the Y valve, but I can't remember what you do with it to manually turn of the HW supply.

I expect someone who does will be along in a minute